/**
 * @file rank/popularize/luogu1044/main.cpp
 * @brief
 * @see
 * @author Ruiming Guo (guoruiming@stu.scu.edu.cn)
 * @copyright 2022
 * @date 2022/7/10 20:20:08
 **/

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
int f[20][20];
int n;
int main() {
  // High rating and good luck!
  scanf("%d", &n);
  for (int i = 0; i <= n; ++i) f[i][0] = 1;
  for (int j = 1; j <= n; ++j)
    for (int i = 0; i <= n; ++i)
      if (i >= 1)
        f[i][j] = f[i - 1][j] + f[i + 1][j - 1];
      else
        f[i][j] = f[i + 1][j - 1];

  printf("%d\n", f[0][n]);
  return 0;
}
